Nonlinear structural analysis and mechanical performance exploration of flexible cable-membrane water-retaining curtains

Water-retaining curtain (WRC) is an effective stratified water intake structure designed to increase discharge water temperature in deep reservoirs. This non-prestressed cable-membrane structure exhibits strongly nonlinear characteristics under hydrodynamic loads, such as mechanism displacements, large deformations, and membrane wrinkling. This study applies the vector form intrinsic finite element (VFIFE) method to investigate the structural response of WRC under water loads. First, the configuration and operating principle of WRC system are described, and an established numerical model incorporating the wrinkling algorithm is introduced and validated through a benchmark example of a square inflated airbag. Subsequently, three innovative layout schemes of WRC, including the slope surface, elliptic paraboloid, and conical surface, are proposed and numerically evaluated, demonstrating that the conical surface achieves the best mechanical performance. The generation and evolution of wrinkling and stresses in the curtain of the conical surface scheme are further examined, indicating that wrinkles are concentrated near the vertical cables and stress peaks occur at the intersections of the vertical cables with curtain edges. Finally, a comprehensive parametric study is conducted to reveal how key structural factors and water level affect the mechanical performance of the conical surface scheme. This study presents the first systematic structural development and evaluation of the WRC system and provides fundamental knowledge and mechanistic insights into its mechanical performance.